I have a 1982 ford f150 the left brake light doesn't work. The turn signal , tail lights , and reverse lights all work. On the right side everything works fine. I replaced the bulb and used a test light and the only power that shows is when the turn signal is on. Any ideas.

 

Sounds like the turnsignal switch. The turnsignal uses the same part of the bulb and the same wiring as the brake light. So since the turnsignal works, that means the bulb and the wiring all the way to the rear are good. The brake and turn signals get mixed together at the turnsignal switch in the steering column.

 

I that the whole black plastic switch or the white part that controls the turn signal.

 

White turn signal switch in the steering column. Common problem on these Ford Trucks. I have bought aftermarket switches and they work but I suggest you do as I have done if you don't like changing them out is go to your local Ford dealer and buy a new OEM switch from them. They are a little more expensive but worth it IMO.

 

With the turn signal and brake light switches unactivated, turn on the hazard flashers. If the left rear hazard light doesn't flash then the turn signal switch is probably bad.

 

I am getting fused, If his turn signal is working how can the switch be bad?



John

 

I had a similar problem caused by that turn signal switch in a 1970 Mustang. The suggestion to see what happens when activating the emergency flashers is IMHO a good one. WRT to that switch, in my case, it depended on the exact placement of the lever at any given time; one or two hairs in either direction and the problem with the brake lights would appear/disappear.

-chris
colorado, usa

 

The brake pedal light switch signal runs through the turnsignal switch. The turnsignal flasher signal also runs to the turnsignal switch. That is because the turnsignals and the brake signals both use the same wires and the same filament in the bulbs at the rear, so the turnsignal switch is a complicated mess of contacts that mixes these two signals together. It lets the brake signal through to both sides when the lever is in the center, and takes the brake signal off the side you move the lever to, and puts the flasher signal onto that side, while leaving the brake signal present on the other side(if you are turning and braking at the same time).

If you have a car or truck with rear amber turnsignals, then you do not have this mess, the turnsignals and the brakes have seperate bulbs and wires, and the turnsignal switch is a simple 3 position switch, and the brake lights are simply fed from the single brake switch on the pedal.

 

Everything including the flashers work , The only thing that doesn't work is that brake light.

 

And the original posters remarks

My question was and still is
Hello


John

 

Inside the turn switch there is a set of contacts (when the turn signal is not activated) that carries the power from the brake light switch (and/or hazard flasher) and routes it to the left brake/turn/hazard bulb. Another set of similar contacts for the right side. If only the left brake/hazard contact is bad all other functions still work.

 

so does that mean I can fix it without replacing the turnsignal switch. Thanks

 

I have had some luck cleaning up the contacts on that switch. I can't remember but I believe a haynes manual shows the what contact is what.

 

Best bet is some spray-on electrical contact cleaner. I get mine at Ace Hardware but any of the big box stores should have it. Spray in and work the switch several times. If that doesn't do it you'll likely have to get a new switch.

 

I tried the hazards and the left side doesn't blink.